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Material differentiation by dual energy CT: initial experience 总被引:9,自引:0,他引:9
Johnson TR Krauss B Sedlmair M Grasruck M Bruder H Morhard D Fink C Weckbach S Lenhard M Schmidt B Flohr T Reiser MF Becker CR 《European radiology》2007,17(6):1510-1517
The aim of this study was to assess the feasibility of a differentiation of iodine from other materials and of different body
tissues using dual energy CT. Ten patients were scanned on a SOMATOM Definition Dual Source CT (DSCT; Siemens, Forchheim,
Germany) system in dual energy mode at tube voltages of 140 and 80 kVp and a ratio of 1:3 between tube currents. Weighted
CT Dose Index ranged between 7 and 8 mGy, remaining markedly below reference dose values for the respective body regions.
Image post-processing with three-material decomposition was applied to differentiate iodine or collagen from other tissue.
The results showed that a differentiation and depiction of contrast material distribution is possible in the brain, the lung,
the liver and the kidneys with or without the underlying tissue of the organ. In angiographies, bone structures can be removed
from the dataset to ease the evaluation of the vessels. The differentiation of collagen makes it possible to depict tendons
and ligaments. Dual energy CT offers a more specific tissue characterization in CT and can improve the assessment of vascular
disease. Further studies are required to draw conclusions on the diagnostic value of the individual applications. 相似文献
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We have studied the possible role of the hypothalamic-pituitary system in the control of the release of plasminogen activator (PA) into peripheral blood of male rats. Plasminogen activator was measured by euglobulin lysis time. Desamino-D- arginine vasopressin (dDAVP) and adrenaline injected i.v. induced an increase in plasma PA as did electrical stimulation of the median eminence (ME), but dDAVP had no effect on plasma PA in hypophysectomized rats. The PA response to ME stimulation was similar in Brattleboro rats (deficient in vasopressin) and adrenalectomized Wistar rats compared with intact Wistar rats, but was abolished by section of the pituitary stalk and was negligible in hypophysectomized rats. The 41-residue corticotropin releasing factor (CRF) had no effect on PA release. Saline extracts of anterior pituitary gland from both normal Wistar and Brattleboro rats produced a dose-dependent increase in plasma PA when injected into normal Wistar rats. The activity of pituitary tissue was abolished by boiling, but not by di-isopropyl fluorophosphate which inactivates PA itself. Thus the anterior pituitary gland of the rat contains a heat-labile factor which stimulates the release of PA from peripheral stores into the circulation. This pituitary factor is released by a hypothalamic factor that is neither vasopressin nor CRF. 相似文献
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O'Brien ME Konopa K Lorigan P Bosquee L Marshall E Bustin F Margerit S Fink C Stigt JA Dingemans AM Hasan B Van Meerbeeck J Baas P 《European journal of cancer (Oxford, England : 1990)》2011,47(15):2322-2330